Finishing polyolefin filamentary textile article and the article obtained therefrom



FNSHING POLYOLEFHJ FILAMENTARY TEX- TILE ARTICLE AND TEE ARTICLE OBTAINED THEREFROl/l Max Levine, Cleveland Heights, Ohio, assignor, by

mesne assignments, to Hercules Powder @ompany, Wilmington, Del, a corporation of Delaware No Drawing. Filed Mar. 15, 1%0, Ser. No. 15,971

16 Claims. (Cl. 117-1395) This invention relates to the treating of filamentary Structures and textile materials of synthetic origin in order to facilitate their handling and construction into yarns and fabrics. This. invention has particular reference to the application of treating agents to yarns consisting essentially of u-olefin polymeric materials. More specifically, it relates to a method of finishing polypropylene yarns and the product obtainable through its practree.

In the formation of fibers, filaments, yarns, threads, cords, tows and the like, hereinafter referred to as filarnentary articles, such as by opening, carding, stretching, drawing, roving, spinning, twisting, winding, and the like the filamentary article is passed over various guides, rolls, pins and other devices. In the handling of the filamentary article over these various devices, it is subjected to rather severe flexing and abrading action which causes the breaking and fraying of many of the individual fibers or filaments. Also, in the processing of fibers, particularly of a synthetic origin, this drawing of the filamentary article over these devices results in the accumulation of a static electric charge which causes it to cling to the equipment, become entwined about it, and cause further breakage of the individual fibers. Similarly, when the filamentary article is converted into a textile product such as by knitting, weaving and the like, further damage to the filamentary article and entanglement occurs. To minimize these difficulties, treating agents which are variously referred to in the art as lubricants, finish oils and conditioning agents are applied to the filamentary article as soon as practicable after its formation.

These treating agents are selected on the basis of their performance with regard to the following functions: reduce surface friction between yarn and guide, prevent the accumulation of excessive static electricity, impart a satisfactory feel or hand to the yarn, show some degree of stability towards aging or oxidating, and the absence of a tendency to injure the yarn itself. Frequently, subsequent processing of the filamentary article or textile product, such as dyeing, necessitates the removal of the treating agent after the handling which required its application. Hence, a conditioning agent which is readily scoured off is desirable. Also, it is advantageous if the treating agent can be formulated as an aqueous solution and, thus, easily and readily applied.

A great number of materials have been suggested in the art as textile treating agents. Generally, these agents are derivatives of long chain fatty materials having between 12 and 18 carbon atoms which have been selected for their known lubricating qualities. These oleaginous materials, however, are not water soluble and, thus, are difficult to apply to the yarn and difiicult to scour off. In order to make these compounds water soluble, they have been reacted with an alkylene oxide such as ethylene oxide to add a polyalkylene oxide chain onto the fatty group. This alkylene oxide end group is Water soluble and, thus, permits the compound to be dispersed in an aqueous solution and washed off in the scouring process. Usually the degree of alkoxylation of the fatty material averages at least about 15 alkylene oxide units and may go as high as several hundred alkylene oxide units detats t pending upon the hydrophobicity of the basic fatty material.

It has been found that when a-olefin polymeric materials are treated with agents such as those having large groups of alkylene oxide units, they exhibit a substantial acceleration in the degradation of the polymer resulting in a loss of strength, an alteration in color, a consequent reduction in quality and various other undesirable effects. Textile goods of polya-olefin yarns which have been treated with agents of this type display an increased tendency to disintegrate under accelerated aging tests and, thus, the agents appear to be more detrimental to the yarn than the friction and abrasion which they are primarily used to reduce.

It has now been found that an alkoxylated hydrocarbon wherein the alkoxylation is well below the amount heretofore used can be readily applied to an wolefin polymer fiber without causing any substantial injury to the material. Furthermore, the products so treated display characteristics of reduced surface friction, satisfactory feel or hand, desirably lower accumulation of static electricity and improved scourability for subsequent treatment. v

In accordance with this invention filamentary articles comprised of a-olefin polymers are treated with a sub stantially saturated alkoxylated hydrocarbon whose alkoxylation is limited to a relatively low amount. This invention has particular application to fiber forming pol meric materials of a-olefins having at least three carbon atoms. The treating agent is, preferably, a long chain fatty hydrocarbon having between 12 and 18 carbon atoms with an average of no more than about four moles of alkylene oxide per mole of hydrocarbon. The treating agent is deposited in the amount of no more than about 3% by weight on the filamentary article which can then be readily processed on conventional textile equip ment into desirable textile products without any substantial injury to the a-olefin polymeric material.

Alkoxylated hydrocarbons whose alkoxylation has been limited to within the range contemplated by this invention do not have significant degradative effects on the polymer of the fibers in comparison with the conventional treating agents used in the art Whose alkoxylation usually averages about 25 or 30 moles per mole of hydrocarbon. Even with this low degree of alkoxylation, these treating agents are sufiiciently water soluble that they can be applied by means of aqueous mediums and exhibit improved susceptibility to scouring in aqueous solutions. They may, also, be applied in organic solvent solutions or as undiluted liquids but application by aqueous medium is preferred. Application of the treating agent may be made by various means, for example, organic solvent solutions or aqueous solutions or dispersions of the alkox ylated hydrocarbon may be sprayed or dripped on the fiber, or the textile materials may be immersed in such solutions or dispersions, or the textile materials, particularly in the case of yarns and filaments, may be passed over a roller coated with such solutions or dispersions. The particular method of application employed will vary depending on the form of the textile used, the concentration of agent desired, the subsequent handling of the textile and the like. Usually no more than about 3% of the alkoxylated hydrocarbon contemplated by the invention need be applied to achieve the beneficial properties desired. The concentration of treatment agent required will, of course, vary with the type of filamentary article, the subsequent handling it must endure and the like'but of particular significance is the lubricating qualities of the hydrocarbon portion of the agent selected. Hydrocarbons having between 12 and 18 carbon atoms are wellknown lubricants and, hence, substantially saturated hydrocarbons of this molecular size range are preferred.

' This invention is applicable to filamentary articles of fiber-forming poly-a-olefins having at least three carbon atoms per monomer unit. Particular advantage; have been found in the practice of this invention in using filamentary articles of stereo-regulated, highly crystalline, high molecular weight polymers of u-olefins of the formula CHFCHR in which R is an alkyl group. Alphaolefins when polymerised with the aid of certain catalysts result in a polymer mixture of crystallizable, isotactic and noncrystallizable ataotlic polymers having a preferentially higher content of the isotactic structure. The isotactic polymers are normally solid, linear, regular head-to-tail crystallizable polymers having substantially no branches longer than R and can be distinguished from the atactic polymers in that substantially all of the asymmetric tertiary main-chain carbon atoms of adjacent monomeric units have the same ster-ic configuration such that the main chain of the macromolecule, when fully extended in a plane, shows substantially all of the R groups on one side of the plane and all of the hydrogen atoms bound to the tertiary carbon atoms on the opposite side. A fuller explanation of stereo-regulation and the a-olefin polymers which are utilizable in this invention may be found in the article by G. Natta and P. Corradini, Rend. Acoad. Maz. Lincei 18, 19 (1955). Filamentary materials formed of stereo-regulated, fiber-forming polypropylene have been found to be particularly well adapted for use in accordance with this invention.

The treating agents of this invention are composed of two general portions one of which is a hydrophobic portion which contributes lubrimting qualities to the material and the second portion is a nonionic residue which is responsible for the hydrophilic character of the agent.

The hydrophobic portion of the treating agent is a substantially saturated hydrocarbon having between 12 and 18 carbon atoms such as the long aliphatic molecules found in natural fats, and the straight, branched or cyclic hydrocarbons of petroleum which have an iodine number of no more than about 60. These substantially saturated hydrocarbons may have a functional group such as a member selected from the class consisting of acid, ester, alcohol, and amide groups. Particular advantages have been found in using treating materials whose hydrophobic portion is the organic ester of a long chain fatty acid such as palmitic, stearic or lauric acid. These acids are preferably esterified with alkanes having between one and four carbon atoms and may be either natural or synthetic products. In contrast, when certain unsaturated hydrocarbons are employed as the hydrophobic portion of the treating agent there is a substantial acceleration in the degradation of the polymer under the influence of heat and light which is not experienced when the above mentioned materials are used or when no treating agent is present on or in the polymer.

The hydrophilic portion of the treating agent molecule is a polyalkylene oxide chain or chains made up of either ethylene oxide or propylene oxide molecules or mixtures of both. This renders the hydrophobic portion more water soluble so that it may be applied in a water solution, may be more readily scoured from the finished article and contribute antistatic qualities to the agent. When the polyalkylene oxide present is of an amount usually found on materials of this type suggested in the art, that is, having an average of about 25 to 30' moles of alkylene oxide, it has been found that they result in a rapid degradation of polyolefin fibers and fabrics. Surprisingly, it has been found that, when the average number of alkylene oxide molecules is controlled to no more than about four moles per mole of hydrocarbon, substantially no degradation is caused thereby. In actual practice, alkoxylation is accomplished by passing the alkylene oxide into the hydrocarbon material and reacting them in such a way that a mixture of products including various fractions with difierent moles of alkylene oxide per fatty molecule results. The amount of alkoxylation in any particular hydrocarbon group can be determined, therefore, by stoichiometric calculation only as an average. Infrared analysis also, as pointed out in the article by C.E. Feazel and E. A. Verchat, J. of Polymer Science, 25, 351 (1957), merely gives the average number of moles of alkylene oxide and, hence, the degree of alkoxylation found useful in this invention is defined as an average. The most common alkoxylating agent is ethylene oxide which has been found particularly advantageous as the molecular units in the hydrophilic portion of the agents contemplated by this invention.

This invention now will be more fully described by the following examples, although it is understood that the invention is not to be limited to the specific conditions contained therein. In these examples, parts and percen of materials are intended as parts and percent by weight.

Example I A 210 denier, 70 filament yarn of stereo-regulated polypropylene having a reduced specific viscosity of 2.3 is passed over a rotating wheel partially immersed in a 8% water emulsion of ethoxylated butyl palrnitate having an average of 3 moles of ethylene oxide per mole of butyl palmitate whereby 1.6% of the ethoxylated butyl palmitate is applied to the yarn. The yarn is stretched to orient the polymer and impart strength to the yarn, twisted and collected in a yarn ypackage. During the processing of the yarn, its passage over guides, stretch rolls and pins does not cause any substantial filamentation or build up in the static electricity generated which causes the yarn to adhere to parts of the equipment and, thus, interfere with its handling. The processing proceeds smoothly and results in a high quality yarn having a soft, full hand.

This yarn is then used to prepare a standard knit fabric for use in an accelerated aging test the results of which are recorded below wherein this yarn is designated as yarn B. A portion of the knit fabric produced as described is scoured to completely remove the treating agent and is, similarly, subjected to the accelerated aging test the results of which are recorded below under the designation yarn A. Similar yarns are produced as described above with the exception that the treating agents used are ethoxylated butyl palmitate having an average of (1) 7 moles of ethylene oxide and (2) 25 moles of ethylene oxide per mole of butyl palrnitate. The results of the accelerated aging tests of knit fabrics made from these yarns with the treating agents thereon are recorded below and designated as yarn C and yarn D, respectively.

The accelerated aging test is conducted by clamping the knit fabric under substantially no tension in an oven controlled at 15 0 C. through which air is circulated at the rate of 1 s.c.f.m. The number of hours under these conditions until the yarn fails is recorded and compared against the yarn without any treating agent to arrive at a degradation index.

The results of this test on the fabrics described are as follows:

Yarn A Yarn B Yarn O Yarn D Degradation index "i 60 14. 4 2. 4

Although the presence of a treating agent results in the index while the ethoxylation of agent on yarn D is Within the ranges normally used in the textile industry for the lubrication and conditioning of synthetic yarns and causes degradation at a substantially higher rate. The treating agent of yarn B, thus, provides not only the desirable characteristics necessary in such lubricating agents but also is easily applied in aqueous solution and does not substantially increase the rate of degradation of the yarn.

Example II Bulk stereo-regulated polypropylene staple having fibers of three denier per filament in lengths of about 1% inches is sprayed during opening with a 14% water emulsion of polyoxyethy'lene stearamide having an average of three moles of ethylene oxide per mole of stearamide to deposit uniformly thereon 1% of the stearamide. The treated bulk fibers are put through a picker, carded to produce a sliver, the sliver drawn and put through roving to produce a roving, and the roving spurr into a yarn. The fibers slide over one another readily and uniformly throughout these operations without forming a ragged uneven sliver or developing an excessive electrostatic charge which would cause it to be attracted to all parts of the rolls and equipment and, thus, prevent the formation of the sliver.

It is well-known that the carding operation is one which is highly susceptible to the generation of electrostatic charges. Using an Electrical Resistance Tester of the type manufactured by the Custom Scientific Instruments Company, the electrostatic charge during carding of this fiber (fiber E) was determined and compared with a fiber similarly prepared but with a treating agent of polyoxyethylene steararnide having an average of 7 moles of ethylene oxide per mole of stearamide (-fiber F). The results are as follows:

Fiber E Fiber F Static index 2. 96 100 Example III A 11% aqueous emulsion of a polyoxyethylene ether of stearyl alcohol having an average of four ethylene oxide units per mole of stearyl alcohol is dripped onto an 1850 denier, 70 filament tow of undrawn stereo-regulated poly(4-methyl-1-pentene) thus depositing 2.3% of the ethoxylated stearyl alcohol on the tow. The undrawn yarn is doubled and then drawn about five times its original length to increase its tenacity and reduce its elongation by substantially orienting the molecules of the polymer. This drawing is accomplished by the use of standard equipment involving a quartet of feed and draw rolls to properly grip the yarn.

During the normal course of drawing synthetic textile materials, a certain small percentage of the filaments of a tow is always stretched, for one reason or another, beyond its drawing limit and is broken. If the tow does not have enough of a lubricant deposited on it prior to drawing, the percentage of broken filaments rises to an undesirable level. Also, if an excess amount of static electricity is produced, the filaments and particularly the broken filaments, have a tendency to adhere to the rolls and become entwined about them causing additional filaments to break. The filamentary material produced in accordance with this example displayed during processing a minimum of broken filaments, an advantageously small number of filaments entwining about the rollers, and no substantial generation of static electricity.

As mentioned above, the treating agents of this invention by reason of their hydrophilic groups may advantageously be applied in aqueous emulsions. These emulsions are suitably prepared with a concentration of between about 5 and about 25% of the treating agent in the emulsion. The emulsion may be sprayed on the fibers, dripped on by means of a perforated pipe, applied by a partially immersed finish roll, or padded on, to mention just a few of the most common methods of applying such agents. It has been found advantageous to apply up to about 3% by weight of the treating agent on the weight of the fiber (o.w.f.). The amount of finish necessary varies depending upon the nature of the processing of the yarn, the subsequent application of the yarn, and the like and may be adjusted to suit these requirements. Treating agent concentrations of between about 0.25% and 1.5% by weight o.w.f. have been found to be particularly advantageous.

The reduced specific viscosity of a polymer is an in dication of its molecular weight and the term as used herein is further described and defined in U.S. Patent No. 2,913,442. It has been found that the characteristics of the fiber vary in accordance with the molecular weight and, hence, the R.S.V. of the polymer of which they are formed. Generally, it is believed for the optimum balance between the characteristics of tenacity, elongation, flexing fatigue, hand, subsequent seta-bi-lity, and the like, the polymer should have a R.S.V. in the neighborhood of about 2 to 2.5.

Since certain changes in the practice of this invention may be readily made Without substantially departing from its spirit or scope it is to be understood that all of the foregoing is to interpreted as being merely illustrative and is not to be construed as limiting or restricting the invention as particularly pointed out and defined in the appended claims.

What is claimed is:

1. A method of treating filamentary articles comprised of an a-olefin polymer having at least three carbon atoms per monomer unit which comprises applying to said filamentary articles a textile conditioning agent consisting essentially of a substantially saturated hydrocarbon alkoxy-lated with an average of no more than about four moles of alkeylene oxide per mole of hydrocarbon said hydrocarbon having between 12 and 18 carbon atoms.

2. A method of treating filamentary articles comprised of a fiber-forming, a-Olefin polymer having at least three carbon atoms per monomer unit which comprises applying to said articles no more than about 3%, by weight of said articles, of a textile conditioning agent consisting essentially of a substantially saturated hydrocarbon alkoxylated with an average of no more than about four moles of alkylene oxide per mole of hydrocarbon said hydrocarbon having between 12 and 18 carbon atoms and a functional group selected from the class consisting of acid, ester, alcohol and amide groups.

3. A method of treating filamentary articles comprised of a stereo-regulated, highly crystalline, high molecular weight polymer of an a-olefin of the formula CH =CHR in which R is an alkyl group which comprises applying to said articles no more than about 3%, by Weight of said articles, of a textile conditioning agent consisting essentially of a substantially saturated organic ester of a long chain fatty acid alkoxylated with an average of no more than about four moles of alkylene oxide per mole of said organic ester.

4. A method of treating filamentary articles comprised of a stereo-regulated, fiber forming polypropylene which comprises applying to said articles no more than about 3%, by weight of said articles, of a textile conditioning agent consisting essentially of an ethoxylated organic ester of a long chain fatty acid selected from the group consisting of palmitic, stearic, and lauric acid said ethoxylation consisting of an average of no more than about four moles of ethylene oxide per mole of said organic ester.

5. A method in accordance with claim 4 in which said organic ester is bu tyl palmitate.

6. A filamentary article comprised of an a-olefin polymer having at least three carbon atoms per monomer unit and having deposited thereon a textile conditioning agent consisting essentially of a substantially saturated hydrocarbon al-koxylated with an average of no more than about four moles of alkylene oxide per mole of hydrocarbon said hydrocarbon having between 12 and 18 carbon atoms.

7. A filamentary article comprised of a fibcr-forming a-olefin polymer having at least three carbon atoms per monomer unit and having deposited thereon no more than about 3%, by weight of said polymer, of a textile conditioning agent consisting essentially of a substantially saturated hydrocarbon alkoxylated with an average of no more than about four moles of alkylene oxide per mole of hydrocarbon said hydrocarbon having between 12 and 18 carbon atoms and a functional group selected from the class consisting of acid, ester, alcohol and amide groups.

8. A filamentary article comprised of a stereo-regulated,

8 highly crystalline, high molecular Weight polymer of an u-olefin of the formula CH =CHR in which R is an alkyl group and having deposited thereon no more than about 3%, by weight of said polymer, of a textile conditioning agent consisting essentially of a substantially saturated organic ester of a long chain fatty acid alkoxylated with an average of no more than about four moles of alltylene oxide per mole of said organic ester.

9. A filamentary article comprised of a stereo-regulated, fiber-forming polypropylene and having deposited thereon no more than about 3%, by weight of said polypropylene, of a textile conditioning agent consisting essentially of an ethoxylated organic ester of a long chain fatty acid selected from the group consisting of palmitic, stearic, and lauric acid said ethoxylation consisting of an average of no more than about four moles of ethylene oxide per mole of said organic ester.

10. A filamentary article in accordance with claim 9 in which said organic ester is butyl palmitate.

References Cited in the file of this patent UNITED STATES PATENTS 2,690,427 Schlatter Sept. 28, 1954 

1. A METHOD OF TREATING FILAMENTARY ARTICLES COMPRISED OF AN A-OLEFIN POLYMER HAVING AT LEAST THREE CARBON ATOMS PER MONOMER UNIT WHICH COMPRISES APPLYING TO SAID FILAMENTARY ARTICLES A TEXTILE CONDITIONING AGENT CONSISTING ESSENTIALLY OF A SUBSTANTIALLY SATURATED HYDROCARBON ALKOXYLATED WITH AN AVERAGE OF NO MORE THAN ABOUT FOUR MOLES OF ALKEYLENE OXIDE PER MOLE OF HYDROCARBON SAID HYDROCARBON HAVING BETWEEN 12 AND 18 CARBON ATOMS. 